There are many ways to define spam. According to one definition, spam is any unwanted e-mail or other electronic message. According to another definition, spam is any unwanted electronic message from an unknown source. Suffice it to say that the problem of spam is serious and growing.
There are various techniques used, disclosed, and under development to help overcome the plague of spam. All these techniques have their advantages and disadvantages. As these techniques are being used in anti-spam products, spammers are innovating at their end to overcome these techniques. Another problem with anti-spam techniques is that there is always a chance of a false positive determination of spam, which can lead to serious difficulty. An e-mail or other electronic message that gets mis-categorized as spam may be an extremely important message, leading to user frustration and annoyance. Hence, it is important to avoid false positives wherever possible. The present invention addresses these issues, is effective at countering spam, and minimizes the false positive problem.